DS Games

[RikSharp]

will do.
do you know if theres and "endgame" like in sacred stones or if it ends after main story?

 

[Poketom]

All the already listed games are damn fine games, only thing I'd add is Shin megami Tensei: Devil Survivor, A JRPG/SRPG with demons.

Just started playing this. It's awesome.

 

[Poketom]

Thanks so far people. I'm on a mission to try and give them all a go.

 

[Magnatek]

will do.
do you know if theres and "endgame" like in sacred stones or if it ends after main story?

No, I don't. I haven't beat it yet. I missed the opportunity to get Marth's best sword, and I'm suffering for it. Make sure you get the "spheres". Sorry for not answering earlier.

 

[Flying-Emu]

I haven't got any use out of my DS in a while bar Final Fantay Tactics Advance 2 & Pokemon Diamond.

Anyone suggest any hidden gems to go find?

The World Ends With You, Scribblenauts, Trauma Center: Under the Knife I and II, Phoenix Wright: Ace Attorney (including its two sequels and Apollo Justice), and Lost in Blue 2 if you can get it for less than $10 USD.

In that order.

 

[SantoUno]

All Castlevania DS games and if you can get your hands on them the GBA Castlevania games, believe me they're awesome and oh-so-timeless.